Difficulties have been encountered in subsea production wells having two tubing strings extending through the wellhead with the closing of a blowout preventer around such dual strings without crushing or damaging such strings because they cannot be oriented by sight.
One effort to solve this problem is shown in the Carl E. Reistle, III et al U.S. Pat. No. 3,554,278 issued Dec. 22, l970. The device disclosed utilizes the configuration of the ram faces to bring the pipe strings into the desired position. Such face configurations include tapered side surfaces and grooves into which the strings are to be positioned when the rams are closed. One problem encountered with such a device is that if one string is directly behind the other, the strings may not be brought into proper position by this device. Another patent showing the use of alignment rams positioned at 90.degree. to the blowout preventer rams is the Howard W. Jones U.S. Pat. No. 3,955,622 issued May 11, 1976.
A structure somewhat similar to the structure of the improved apparatus of the present invention is shown in the Marvin R. Jones et al U.S. Pat. No. 3,957,113 issued May 18, 1976 and discloses a dual ram structure to be used with a blowout preventer which engages a pipe section and causes it to rotate to unscrew the joints. The rotation is imparted by jaws with teeth engaging the pipe section and with cam surface engagement with its carrier so that as the rams close, the jaws move to the sides creating a moment couple on the pipe section.